Welding and Processing Technology of Foreign Standard Structural Steel
As a high-quality steel material, foreign standard structural steel is widely used in construction, bridges, and mechanical manufacturing. The welding and processing technology of this steel is crucial for ensuring product quality and performance. Below is a detailed introduction to the welding and processing techniques of foreign standard structural steel.
Welding Technology of Foreign Standard Structural Steel
Welding is a key process for foreign standard structural steel, directly impacting the structural performance and service life of the product. Welding technology mainly involves three stages: pre-welding preparation, welding process control, and post-welding treatment.
Pre-welding Preparation
Before welding, the surface of the foreign standard structural steel must be thoroughly cleaned to remove any oil, rust, and oxidation scale, ensuring the cleanliness of the weld area. Additionally, appropriate welding materials, welding parameters, and preheating temperatures must be selected according to design requirements. The choice of welding material should match the chemical composition and mechanical properties of the base material to ensure that the mechanical properties and metallurgical structure of the weld are similar or identical to those of the base material.
Welding Process Control
During welding, it is crucial to follow operational standards and control the shape, size, and position of the welds. Common welding methods include manual arc welding, gas shielded welding, and submerged arc welding. Manual arc welding is suitable for welding in various positions but requires higher skill levels; gas shielded welding is widely used in steel structure welding due to its high efficiency and excellent weld quality; submerged arc welding is suitable for long welds and large-scale production, providing a stable welding process and high-quality welds.
To minimize deformation and stress, techniques such as symmetrical segmented welding and cross-symmetrical welding may be used. Additionally, controlling welding current, voltage, and speed is essential to ensure weld quality.
Post-welding Treatment
After welding, the welds must be inspected, repaired, and corrected as needed. Inspections aim to identify and eliminate weld defects such as pores, slag inclusions, and cracks, using visual inspections, flaw detection, or ultrasonic testing. Repairs restore the mechanical properties and metallurgical structure of the weld, which can be achieved through grinding, re-welding, and heat treatment. Correction is performed to eliminate or reduce deformation and stress caused by welding, using mechanical correction, flame straightening, or stress-relief heat treatment.
Processing Technology of Foreign Standard Structural Steel
The processing technology of foreign standard structural steel primarily includes cutting, drilling, bending, and assembly.
Cutting
Cutting is the first step in processing foreign standard structural steel. Common cutting methods include oxy-fuel cutting, plasma cutting, and laser cutting. Oxy-fuel cutting is suitable for thicker steel, offering fast cutting speeds but with a larger heat-affected zone; plasma cutting and laser cutting are more suitable for thinner steel, providing higher precision and smaller heat-affected zones.
Drilling
Drilling is a common process in structural steel processing, which can be performed using methods such as drilling, punching, and milling. Drilling is suitable for smaller diameter holes, punching for larger diameter holes, and milling for holes requiring higher precision.
Bending
Bending is an important deformation process in structural steel processing and can be performed using methods such as press bending, roll bending, and stretch bending. Press bending is suitable for small-radius curves, roll bending for large-radius curves, and stretch bending for high-precision curves.
Assembly
Assembly is the final step in processing foreign standard structural steel, typically performed using welding, bolting, or riveting. Welding offers high connection strength but requires high skill levels; bolting and riveting are suitable for parts that need to be disassembled or replaced.
Conclusion
In summary, the welding and processing technology of foreign standard structural steel is essential for ensuring product quality and performance. In practical applications, appropriate welding methods and processing techniques should be selected based on specific requirements and conditions to ensure that the product meets design specifications in terms of quality and performance.